For those interested in sea level rise the recent release of a 660 square km (255 square miles) iceberg from the Pine Island ice shelf is an interesting development. Although a great deal of ice has melted world wide, much of it is already in the sea and has not contributed to sea level rise. However, when the floating ice breaks up, the glacier it was buttressing starts to slip more quickly towards the sea, where it will melt faster. The Pine Island glacier has already nearly doubled its speed towards the sea and the ice shelf is melting from underneath very quickly. The glacier is already a major contributor to the 200 mm sea level rise that we have had so far, half of which has been from thermal expansion.

Pine Island and its adjoining Thwaits glacier together are the largest ice drainage basins in the world, and combined could contribute one or two meters of sea level rise. Not that it will melt suddenly or on its own but it is a big indicator of what is happening all round Antarctica.